TDStuart Tuning Adventure

[tdstuart]

I suggested that 30 or so pages ago, but nobody wanted to entertain that possibility. I really feel like there is a mechanical issue at play here. A simple compression test might give him a clue.

There is a mechanical issue causing loss in power.

I don't think it will affect the tuning of the car. But I also wanted to learn to tune so I could see if any issues stood out to me.

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[Pws6]

I suggested that 30 or so pages ago, but nobody wanted to entertain that possibility. I really feel like there is a mechanical issue at play here. A simple compression test might give him a clue.

I suggest that in the last thread and OP called me a retard

 

[tdstuart]

Is there a possibility the cams are not degreed correctly ? I’m sure they were installed “dot to dot” and not validated with a degree wheel kit to the cam grinders spec.

You can't really "degree" them. They fit into the phasers only one way and you line up the timing chains with the marks and thats it.

Unless I skipped a tooth or my timing procedure is off (which from my research would be very noticeable and the car would detect), you can't really mess it up.

 

[tdstuart]

I suggest that in the last thread and OP called me a retard

Haha which post, I don't tend to call people retards on here, even if I disagree with their opinions.

 

[K4fxd]

You can't really "degree" them.

You use offset keys to put the cams back into time if they are off.

 

[K4fxd]

I know it is hot there but these guys do have a point. A comp test would rule out a lot of things.

 

[tdstuart]

@tdstuart if you log your desired airflow and MAF, they should match very closely. Based on the log you posted, yours is off as much as 30%. Assuming your MAF, TB, and Injector data are correct, this can only point to the SD model as being the problem. That said, the more I think about it, the more I think you can get it in the ballpark without actually having to measure the manifold pressure. You see, the throttle body flow is modelled in the logic and the blade angle is sent to a pre-calculated position to achieve a desired airflow. Then the MAF reads the actual airflow and a feedback loop correction is made, but the feedback loop intentionally has limitations. Therefore, you can tune the SD model and get it "in the ballpark" by modifying it until the desired airflow matches up to MAF.

If this were my car, I would do the following steps:
1. Disable the throttle feedback loop. The feedback loop corrects errors so it will mask problems that you want to correct. This is a temporary change just until the SD model is calibrated, and would be disabled by setting auF0080 to 0.
2. Lock it in to one Mapped Point in order to focus on just tuning that one. I would start with Mapped Point 5 since that is where it hovers at cruise. This is done by setting auF33355 to all 5's. This will force it to MP5 at all times not at idle or WOT.
3. With the above changes, desired airflow and MAF can be logged and compared to see the "raw" error. Calculated MAP, rpm, MP5 weight should be logged as well.
4. Start tuning the MP5 SD model. This will be iterative and each value only applies to that specific rpm. It's best to try holding engine speed constant and varying the load with the throttle as best you can. Specifically, I would start by modifying the slope values, auF33197, as this will scale the entire curve up and down by roughly the same % change. My bet is the slope needs to be scaled up and I'd start in 10% increments and see how the MAF vs desired airflow error responds. If there is no discernable change, I'd try larger adjustments. I would try to get the error under 5% by modifying just the slope values.
5. Put auF0080 back stock to re-activate the feedback correction.

Once this is done, MP5 SD model is fairly well calibrated and you'd have a decision to make. You can elect to just leave auF33355 as it is and just let it use MP5 at all times not idle and WOT. Lund often takes this approach, except they don't bother using a high efficiency point like MP5. Or, if you are successful and want to continue on, you can proceed to other Mapped Points that you might want to use. At this point, you can begin to see why many, such as myself, try to reduce the number of active mapped points as much as possible. I'm running only 5 points, and others have reported similar strategies.

Locked to MP5/MP17

Car feels like it is always at 10% throttle even at 50%. Doesn't "give me more power" until i floor it enough to switch to OP.

Is there something else I need to change?

Log attached

 

[tdstuart]

I know it is hot there but these guys do have a point. A comp test would rule out a lot of things.

I can set aside time to do it.

I personally don't think its a compression issue. And even if all the cylinders are down a bit no reason it should affect my tune but not Lunds.

 

[engineermike]

Locked to MP5/MP17

Car feels like it is always at 10% throttle even at 50%. Doesn't "give me more power" until i floor it enough to switch to OP.

Is there something else I need to change?

Log attached

If you read the instruction, the intent wasn't for it to instantly be fixed when you lock it to one mapped point. The intent was to tune that mapped point, then move on to the next one. It was never going to fix anything by simply locking it to a mapped point.

You made it to the 3rd step. At this point, you'd proceed to step 4 and 5 and start calibrating MP5/17. You'll want to log the weight of just those two points to ensure you're tuning the right one. If you look at desired airflow vs MAF, you see a big discrepancy. This is because the throttle isn't opening enough, which is because the SD model is way off. In the instructions I posted, you would start changing the SD slope for until the MAF and desired airflow meet up.

 

[tdstuart]

If you read the instruction, the intent wasn't for it to instantly be fixed when you lock it to one mapped point. The intent was to tune that mapped point, then move on to the next one. It was never going to fix anything by simply locking it to a mapped point.

At this point, you'd start calibrating MP5/17. You'll want to log the weight of just those two points to ensure you're tuning the right one. If you look at desired airflow vs MAF, you see a big discrepancy. This is because the throttle isn't opening enough, which is because the SD model is way off. In the instructions I posted, you would start changing the SD slope for until the MAF and desired airflow meet up.

Seems to be way way way off. Are you sure it’s just the SD that needs to be reworked and not something limiting torque?

 

[engineermike]

Seems to be way way way off. Are you sure it’s just the SD that needs to be reworked and not something limiting torque?

I'm telling you what I would do if it were mine. There are multiple indicators that your SD model is off, all the same direction, and the data matches the theory. I really don't see how the torque model could cause this issue.

 

[tdstuart]

I'm telling you what I would do if it were mine. There are multiple indicators that your SD model is off, all the same direction, and the data matches the theory. I really don't see how the torque model could cause this issue.

I tried increasing sd like you suggested and didn't see any changes. I multiplied it all by 2 and the car just uses different cam positions and doesn't use MP5 or MP17 at all now.

Car is still like 1/3 of the requested torque.

 

[tdstuart]

I tried increasing sd like you suggested and didn't see any changes. I multiplied it all by 2 and the car just uses different cam positions and doesn't use MP5 or MP17 at all now.

Car is still like 1/3 of the requested torque.

Looks like spark is constantly sitting at "base" instead of "borderline". I think this is causing the low power issue.

 

[engineermike]

I tried increasing sd like you suggested and didn't see any changes. I multiplied it all by 2 and the car just uses different cam positions and doesn't use MP5 or MP17 at all now.

Take it one step at a time. You can not tune an individual mapped point unless it’s isolated. You have to make it only use the target mapped point (except idle and wot) before even beginning to tune it. This may require turning the imrc to constant closed position. Once that is done you can tune the sd model. Have you logged vct schedule mode to verify its staying in fuel economy or drivability?

 

[engineermike]

Looks like spark is constantly sitting at "base" instead of "borderline". I think this is causing the low power issue.

No, base is mbt, where it makes the most power and is most efficient. Most coyotes run base timing at light load and borderline at heavy load where it becomes knock limited.

The low power is 100% due to the lack of throttle opening. Again, compare maf to desired airflow. If you actually got desired airflow it would make way more torque.

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